Multiunit variable condenser



I 'Sept.- 7,' 1937. KOCH 2,092,675

MULTIUNIT VARIABLE CONDENSER Film; April 6, 192a 2 Sheets-Sheet 1 /Z 70 5 7 J/ JO g4 25 X? I 2% l rcs- E ATTORNEY P 7, 1937. F. KOCH MULTIUNIT VARIABLE CONDENSER Filed April 6, 1923 TIE-7 2 Sheets -Sheet 2 ATTORNEY Patented Sept. 7, 1937 UNITED STATES PATENT OFFICE Application April 6, 1928, Serial No. 268,068 In Germany September 24, 1927 12 Claims.

This invention relates to variable condensers for use in radio circuits, and particularly to a condenser of multi-unit type or consisting of a plurality of condensers independently adjustable for tuning a radio receiving circuit into resonance with selected stations.

One object of the invention is to provide a multi-unit condenser the units of which may be adjusted and set to enable the user of a radio 10 receiver to instantly tune his receiver into exact resonance with any transmitting station of a plurality of selected stations.

A further object of the invention is to provide a switch-indicator whereby one and the same oper- 15 ation of a control member will indicate the station selected and connect the proper pretuned condenser unit with the receiving circuit for the reception of signals from that particular station.

20 A still further object of the invention is to provide a condenser of the character set forth including a supplementary continuously variable condenser unit which may be adjusted independcntly of a tuned unit or units for general pur- 25 poses in tuning the receiver throughout its entire frequency range.

A still further object of the invention is to provide a multi-unit condenser of compact type and one in which one or more units of a condenser of this type may be coupled for single-control action to companion units of one or more similar condensers Where two or more gang condensers are used for tuning the receiving circuit.

With these and other objects in view, the invention consists of the features of construction, combination and arrangement of parts, hereinafter fully described and claimed, reference being had to the accompanying drawings, in which:

Figure 1 is a face view of a supporting panel showing the condenser control device mounted thereon.

Figure 1a is a View showing two inulti-unit condensers embodying my invention coupled for switching actions in unison.

Figure 2 is a view in side elevation of the condenser, the panel and parts of a coupling connection appearing in section.

Figure 3 is a vertical section on an enlarged scale through one of the condenser units.

" Figure 4 is a view in side elevation of a condenser unit.

Figure 5 is a similar view omitting the shield disk and showing the insulator strip of the coil 55 spring conductor partly broken away to expose said conductor.

Figures 6, '7 and 8 are sectional views taken, respectively, on the lines 6--6, l'l and 8-8 of Figure 3.

Figure 9 is a vertical section through the panel and parts of the indicator-switch, and showing the construction of the same and the control device for the auxiliary condenser unit.

Figure 10 is a diagrammatic view of the condenser units and the switch connections for selectively switching the units into and out of a 10 receiving circuit.

Figure 11 is a perspective view of .a receiver embodying the invention.

In the illustrated embodiment of my invention as herein disclosed, I provide a multiple condenser A comprising a frame structure composed of a series of intermediate disks I of insulating material, and front and rear disks 2 and 3, also of insulating material, which disks are fixedly related and united and held in position by tie bolts or rods 4, spacing washers or the like 5, and nuts 6. The intermediate frame disks l are arranged in pairs, the pairs of disks and the disks of the pairs being properly spaced with relation to each other and to the disks 2 and 3. Each pair of disks serves as the outer frame elements of a condenser unit of which any desired number may be employed in the multiple condenser. As shown in the present instance, seven such condenser units are used, generally denoted l, 8, 9, I0, ll, l2 and I3, respectively, each unit consisting, as clearly shown in Figure 3, of a pair of disks I, a stator formed of a suitable number of spaced conductor plates [4, a rotor formed of a suitable number of coacting conductor plates l5, and separators between the opposed faces of the plates 14 and [5 comprising sheets or layers of a suitable dielectric material It, such as mica, the stationary elements of each condenser unit, to wit, the insulating frame disks l, stator plates [4 and sheets of dielectric material l6, being properly united and maintained in working position by bolts and nuts or other suitable fastenings l1 and insulating washers l8. The rotor plates 15 are mounted for movement within a given arc upon the angular central portion of a shaft l9 having end journals 20 of circular form which are fitted to turn Within bearing openings in the disks l. The plates l5 are coupled 50 for movement in unison to a connecting member or head 2 I. bearing at its sides against the inner faces of the disks I so as to guide the plates IS in a true path. The connecting member or head 2| is provided with a screw stud or stem 22 receiving an internally screw-threaded adjusting and clamping knob 23. The base of this knob is adapted to ride upon the peripheral edges of the disks l and to have clamping engagement therewith, so that, by loosening the knob 23, the rotor will be free for movement and adjustment in the usual manner to vary the effective capacity of the condenser unit, after which by screwing up the knob 23 and bringing it into frictional binding engagement with the edges of the disks i the rotor will be held in the position to which it has been adjusted so as to maintain the condenser unit at the predetermined effective capacity value.

The units '5 to E3, inclusive, may be of the same or different capacity ranges for tuning a circuit to different frequencies within the same or different band ranges, and the units l to i2, inclusive, are designed to be adjusted to tune a receiver in which the condenser is included into resonance with selected stations, and to be main tained in adjusted or set condition so that the user of the receiver may instantly tune into any one of the selected stations, while the condenser unit is is a supplementary unit designed to be adjusted at any time, by means of a control device, for fishing actions or tuning in stations within the entire frequency range of the circuit in which the multiple condenser is arranged. Thus while any one or more of the units '5 to H2, inclusive, may be set for the tuning in of arbitrary stations, the unit is may be used for general purposes in the tuning in of any stations desired. The stators of all the units are connected by conductors i 8 9 ic i i it and it to switch points l 23 d ifii H 2 and i3 mounted upon the disk 2, which forms a switch board arranged immediately in rear of a supporting panel or other suitable support 2% on which the condenser may be mounted directly by means of the bolts 4 or by auxiliary fastening means engaging said bolts. The switch points form part of an indicatorswitch comprising a stationary indicator disk 25 arranged at the front of the panel 24 and having a series of observation slots or openings 2% equal in number to the condenser units. and designed to receive placards bearing appropriate indicia. Thus, for instance, six of these placards may bear the call letters or symbols of stations for which the condenser units '1 to i2, inclusive, are set for tuning actions, while the seventh placard, pertaining to the supplementary condenser unit 53, may bear the letter'm or any other symbol indicating that it is an extra unitnot tuned to any station but adapted to be adjusted for general tuning purposes. Arranged behind the disk and between the same and the panel is an indicator arm or pointer 2'! adjustable into registry with any one of the indicating placards by means of an operating arm 28 carrying a screw stem is movable in a guide slot 3:! in the disk 25 and on which is fitted an operating knob 35 which may be adjusted on the stem to bear against the disk so as to fix the pointer 21 in any of the positions to which it is adjusted. The pointer 2i and operating arm 28 are fixed to a hollow shaft 32 mounted to turn in suitable bearing openings in the disk 2 and panel 2d, whereby the pointer 2? is coupled to the arm 28 for movement there with. To the shaft 32 is also connected a switch arm 33 which is adjustable with the pointer for engagement with the particular one of the series of switch points E -fis connected with the condenser unit for tuning in the station indicated by the pointer 27. On the disk 2 is a binding post or terminal 3 3 from which leads a conductor 355 for connecting the switch member 33 and condenser unit coupled thereto to a part or branch of the receiver circuit. This binding post 3d is electrically connected with the shaft 32 by a conductor wire 36 having a coiled spring portion 371' surrounding and connected to the inner end of said shaft, the coils of which spring contract and expand as the shaft is turned in one direction or the other so that a positive connection between the conductor 34 and the shaft may be made to reduce losses caused by wiping contacts and other types of impositive contacts.

The rotors of all the condenser units, 1 to l3, inclusive, are connected to a common conductor 3% leading to a binding post or nut 39 on the rear insulating disk 3, from which binding post or nut a conductor it may lead to the part or branch of the receiver circuit with which the rotors are to be electrically connected. Connection between the common conductor 38 and each rotor is made by means of a conductor wire 4!, similar to the wire 36, and having a coiled spring portion :2 which surrounds an end of the rotor shaft 59 projecting through and beyond the outer face of one of the associated disks l, and to which projecting end of the shaft said coiled spring is connected, the spring 42 thus contracting and expanding as the shaft it turns in one direction or the other to permit of such motion of the shaft and of a positive connection being made therewith, with the advantages previously stated with respect to the use of the spring 3%. This conductor 4! and its spring portion 32 may be covered by an insulation strip "53 of mica or other suitable electric insulating or dielectric material. With this construction it will be seen that the stators and rotors of the condenser units may be selectively connected with and disconnected from the electric circuit by adjustment of the switch member 33 to engage a determined switch contact. If desired, the capacity of any condenser unit of the series may be increased, while maintaining a desirable spacing relationship of the parts, by arranging on that side of the disk I bearing the rotor conductor ii of the unit, and in the air gap or space between the same and adjacent unit at the same side, a plate 3 3 serving as an auxiliary stator plate held by the bolts 4 and separated from the conductor M by the dielectric separator strip 53 and which may be connected for such purpose by a conductor 1 with one of the bolts ill, the elements 5! and it thus serving to form an auxiliary condenser of small capacity, one active element of which is connected with the rotor shaft l9 and main rotor plates i5 and the other active element with the bolt ii in question and through the same with the main rotor plates M. The plate M may also, if desired, be adapted to serve the function of a shield in order to prevent inter-capacity effects between adjacent capacity units, which plate 44, in such case, may be suitably grounded, as through one of the bolts 1 and a ground connection as shown at Ma in Fig. 2.

The rotor of the fishing condenser unit i3 has its shaft extended, as indicated at $5 in Figure 9, and the extended portion of said shaft projects outwardly through and is journaled in the hollow switch shaft 32. Upon the outer end of the shaft extension 15 is mounted a control member or dial d6 disposed upon the outer side of the indicator disk 25 and provided with scale graduations 51 which may be suitably designated and arranged for cooperation with one of the openings 26 or an indicating mark on the disk 25, so that degrees of movement of the rotor of condenser unit l3 may be determined for adjustment of said condenser to any kilocycle or wave meter point in tuning. If desired, the capacity of this condenser unit l3 may, between minimum and maximum, differ between the minimum and maximum capacities of all or some of the other condenser units or cover the entire frequency range of the radio circuit in which the condenser is used.

In practice, a single multiple condenser of the construction above-described, or two or more of such multiple condensers, may be employed for tuning a radio circuit, and where more than a single multiple condenser is used a single control for operating like movable parts of the multiple condensers may be employed. For example, the switch arm 33 of condenser A may be provided with an arm 48 movable with the switch arm 33 and adapted to be coupled by means of a link 49 to the corresponding switch arm of a second multiple condenser A, whereby the switch arms of both condensers may, upon operation of a single operating arm 28, be adjusted to engage the same switch points of the multiple condensers to connect the proper condenser units of the multiple condensers into the receiver circuit for a calibrated tuning action. Also the rotor of condenser unit I3 may be provided with an arm 50 adapted to be coupled by a link 5| with the rotor of the same unit of the second multiple condenser, so that both of said condenser A units may be adjusted in unison by movement of one and the same control dial 46. Similarly the switch devices and rotors of the auxiliary condenser units of any number of multiple condensers used in a receiver may be coupled together for simultaneous adjustments.

The use of a multiple unit condenser embodying my invention in a receiving circuit will be found of great advantage under many conditions. For military or postal service, where troops or aircraft pilots are operating in a certain area where there are a number of communicating radio stations, those in field service may tune their receivers to these particular stations in a fixed and exact manner, so that by the simple manipulation of a switch any station in the area while operating may be instantly tuned in. Receivers used on ships or aircraft flying over seas equipped with my multiple unit condensers may set their receivers for instantly tuning in any one of a series of transmitting or beacon stations, so that instructions or guide directions may be received at the expenditure of the least amount of time and trouble. Corporations or other large organizations, of various kinds, operating a number of stations and having men working in the field will also find receivers equipped with my multiple unit condensers of great advantage, in that the employees may tune in instantly with any one of the stations at a predetermined time or times for the purpose of receiving information or instructions to be given them. Persons using a radio receiving set for amusement in the home will also find a set equipped with my invention to be of advantage, inasmuch as such person may set his receiver for the instant tuning in of any one of a number of favorite stations or those giving the programs he likes best, while he may, if he desires, use the condenser unit l3 for general tuning purposes in bringing in other stations.

An important feature of my invention is that the condenser units and the switch contacts of their switch mechanism are arranged on the inner or rear side of the panel or support 24, while the controlling elements of the switch contacts are arranged on the outer or front side of said panel or support 24, which panel or support may form the front wall of a radio receiver cabinet R, the cover or closure 13 of which is capable of being sealed or locked, as by means of any approved type of lock B against access by persons unauthorized to have access thereto, so that the user may operate the external controls to tune the receiver to certain fixed stations, and to others, if desired, while he is prevented from having access to the tuning condenser or other working parts of the receiver within the cabinet. Hence the condenser units 1 to H2, inclusive, may be pretuned to certain stations by an authorized person and the cabinet then locked or sealed to prevent any unauthorized person from tampering with the adjusted condenser units so as to cause them to be injured or to get out of adjustment. By this means field employees of a concern operating a number of stations may be provided with a locked or sealed receiver whose tuning units are pretuned to such stations, so that an employee by adjusting a switch may tune to any of the stations for the purpose of receiving information or instructions. Employees not particularly skilled in the use of radio receivers may thereby be enabled to communicate when desired or at given times with any one or more of a number of stations conducted by the employing company without the necessity of performing any tuning operations. Also the invention provides a very compact type of tuner for the purpose described, of great value for use for this reason in portable sets and for aircraft and field service use, etc. The use of a locked or sealed set of this character, furthermore, will be found of great advantage for military, naval or other secret communication purposes in permitting men on detail to communicate with stations of unknown sending frequencies, and whose frequencies it is intended to be kept secret. Other similar uses and advantages of the invention in this connection will be readily apparent to those versed in the art, in the light of the foregoing disclosure, without a further and extended description.

This new and improved tuning condenser is i of small capacity and in a compact manner in place of the solid dielectric condensers commonly employed;

(2) The requirements for rapid communication work may be fulfilled because the switch lever provides for connecting any of the pre-set condenser units, or the fishing unit, into a circuit without disturbing the settings of the individual condensers;

(3) This type of condenser, when arranged for low values of capacity, does not introduce losses which would be detrimental with respect to operating efficiency; and

(4) Two such condensers may be employ-ed in tandem and suitably coupled, as in case of condensers A and A, to afford pre-adjusted coordinate circuit control actions, consequently maximum eificiency on any one wave length.

While the construction of the condenser as disclosed is preferred. it will, of course, be understood that such disclosure is given merely as an example, and that various changes in the form, arrangement and proportions of the parts may be made within the scope of the appended claims, without departing from the spirit or sacrificing any of the advantages of the invention.

Having thus described my invention, I claim:

1. In a tuner for radio circuits, a gang of separate and independent condenser units each including capacitor elements relatively movable to vary its capacity, means for independently adjusting the movable elements of the respective units, whereby the several units may be set for pretuning a circuit to different working frequencies, the units of the gang being closely arranged side by side and each individual unit being separated from an adj cent unit by insulating means comprising partitions of insulating material at opposite sides of said unit between which the capacitor elements thereof are disposed, the partitions between adjacent units be ing further insulated by air gaps therebetween,

' and switching means for selectively cutting said condenser units into the circuit.

2. A tuner for radio circuits comprising a group F of independent variable condenser units disposed in close proximity to each other, and each comprising a set of stator and rotor plates, spaced disks of insulating material on opposite sides of the set of plates and separator sheets of solid dielectric material between the plates and between the plates and disks, the'insulation disks of the adjacent units being separated by air gaps, means for independently adjusting the rotors of the units, whereby the several units may be pre-set for pretuning a radio circuit to different working frequencies, and switching means for selectively cutting the condenser units into the radio circuit.

3. In a tuner for radio circuits a supporting panel, a multiple condenser disposed at the rear of the panel and comprising, a plurality of separate and independent condenser units arranged side by side and spaced by air gaps therebetween, each unit comprising frame members and capacitor elements relatively adjustable for varying the capacity of the unit to tune a circuit to different working frequencies, means for independently adjusting said condenser units, a continuously variable condenser unit at the rear of the panel and similarly spaced from one of the first-named units, said continuously variable condenser unit having an adjusting shaft extending outwardly through the panel, a switch device for selectively cutting said units into or out of the radio circuit said switch device comprising a shaft extending through the panel coaxially with said adjusting shaft, contacts mounted at the rear of the panel concentric with said shafts, and a rotary contact member mounted upon the inner end of the switch shaft at the rear of the panel for engagement with said contacts, and operating members mounted upon the outer ends of the shafts at the front of the panel for independently shifting said rotary contact member and the rotatable member of said continuously variable condenser.

4. In a tuner for radio circuits, a plurality of condenser units arranged side by side and each including an element movable to vary its capacity, means for independently adjusting the movable element of each unit, whereby the several units may be set for pretuning a circuit to different working frequencies, insulating partitions at opposite sides of each unit, the partitions between adjacent units being separated by air gaps, shields in said gaps and connected to the respective units, and switching means for selectively cutting said condenser units into a radio circuit.

5. In a tuner for radio circuits, a plurality of condenser units arranged side by side and each including an element movable relatively to a coacting element to vary its capacity, means for adjusting the movable element of each condenser unit, whereby each condenser unit may be adjusted for tuning a circuit to different working frequencies, said condenser units being separated by air gaps, compacitatively coupled shield conductors disposed in said gaps and conductively connected with the coacting elements of each, and switching means for selectively cutting said condenser units into a radio circuit.

6. A tuner for radio circuits comprising a gang of independent condenser units, each consisting of a pair of spaced frame disks of insulation material, electrodes between the disks of each unit relatively adjustable for varying the effective capacity of the unit independently of any other unit, whereby the units may be pre-set for tuning a circuit to different working frequencies, and

ly adjusting its electrodes, the adjusting means applied to one of the end units of the gang consisting of an operating shaft, an operating member for rotating the shaft, and a rotary switch device arranged concentric with said shaft for selectively cutting said units into the circuit.

7. In a tuner for radio circuits for tuning a circuit to a plurality of difierent working frequencies, a supporting panel, an indicating means on the outer side of said panel having a plurality of frequency indicating points, a multiple condenser comprising a plurality of independently adjustable units arranged on the inner side of the panel each adapted to be adjusted and to different effective values for tuning the circuit to different frequencies and a continuously variable unit for tuning the circuit throughout a desired frequency range, said continuously variable unit having an operating shaft extending therefrom outwardly through the panel, means on the outer side of the panel for operating said shaft, and a switch mechanism comprising contacts, one for each condenser unit and frequency indicating point, located on the inner side of the panel, a second shaft mounted concentric with the first-named shaft and extending through and having portions disposed on both sides of the panel, an operating element connected to the portion of said second shaft disposed on the outer side of the panel and having connected therewith an indicator member movable thereby to registering coaction with any of said frequency indicating points, and a switch member located wholly on the inner side of the panel and connected with the portion of the second shaft disposed on said side of the panel, said switch member being thereby connected by the second shaft to said indicator for movement therewith and operating in such movement when the indicator reaches an indicating position to simultaneously connect the radio circuitwith the condenser unit adjusted to tune the circuit to the frequency indicated thereby.

8. In a tuner for radio circuits, a gang condenser comprising a series of individual condenser units arranged one in rear of the other in spaced relation with air gaps therebetween and each embodying a frame and capacitance elements comprising a stator and a rotor, means for adjusting said rotor to vary the capacity of the unit, and whereby the different units may be adjusted to tune the circuit to different frequencies, electrostatic shields disposed in the air gaps between the units and coupled to the respective units, and a switch for selectively cutting the condenser units in or out of a radio circuit.

9, A tuner for radio circuits comprising a group of individual variable condenser units closely arranged in gang formation and each including a stator element and a rotor element adjustable for setting said units for tuning a circuit to different working frequencies, means whereby the rotor elements of the respective units may be adjusted with relation to their stator elements to tune the circuit to different frequencies, a supplemental condenser unit including stator and rotor elements continuously variable for tuning the circuit over a desired frequency range, the respective units being separated from each other by air gaps, shields in said gaps conductively and ca- 5 pacitatively coupled to the stator and rotor elements of the respective units, means for operating the rotor element of the supplemental unit, and switch mechanism for selectively connecting the condenser units with the radio circuit.

10. In a tuner for radio circuits, a gang of variable condenser units arranged side by side in spaced relation with air gaps therebetween and each comprising frame members and relatively adjustable capacitance elements for selectively tuning a radio circuit to different working fre quencies and non-conducting material separati ing said elements from each other, means for relatively adjusting the capacitance elements of each condenser unit, shields disposed in the air gaps and conductively connected with the capacitance elements of the units and a switch device for selectively connecting the units of the gang with the circuit.

11. In a tuner for radio circuits, a supporting panel, a primary multiple condenser arranged at the rear of the panel and comprising a plurality of separate and independent adjustable condenser units with means for adjusting and setting the same to different effective capacity values, a continuously variable condenser unit interposed between the first-named condenser units and the panel and including a rotary member having an adjusting shaft extending outwardly through said panel, switch contacts at the rear of the panel and connected with said units, a rotatable contact arm at the rear of the panel and engageable with said contacts to selectively cut the pre-set condenser units into the radio circuit, means at the outer side of the panel and acting on said shaft for adjusting the rotary member of the continuously variable condenser imit, an operating element for the contact arm disposed at the front of the panel, a rotary connecting element extending through the panel and connecting said operating element with the contact arm whereby the latter may be moved to contact engaging positions, a secondary multiple condenser arranged at the rear of the panel and comprising condenser units, switch contacts and a rotary contact arm for cooperation with such parts of the primary condenser, a motion transmitting element on the rotary connecting element of the primary condenser, and a motion transmitting connection between the said motion transmitting element and the switch arm of the secondary condenser coupling said switch arms for movement in unison.

12. In a tuner for radio circuits, a supporting panel, a condenser arranged upon the rear side of said panel and comprising a plurality of independent condenser units, each including a stator and a. rotor, means located wholly at the rear side of the panel with each rotor of a certain number of said condenser units and selectively operable whereby each rotor may be adjusted and fixed in adjusted position independent of the rotor of any other condenser unit to tune the circuit to different working frequencies, an indicator element at the front of the panel provided with indicators equal in number to the condenser units, means including a rotary operating device operable from the front side of the panel for adjusting the rotor of another condenser unit, a switch device including a movable switch contact located wholly at the rear of the panel so as to be concealed in entirety from View at the front of the panel and relatively movable to different working positions for independently connecting the condenser units with or disconnecting them from the circuit, an operating element for the switch device located at the front of the panel, a connecting member extending through the panel and coupling said operating element with the concealed movable switch contact whereby the latter may be operated from the front of the panel, and a pointer movable with said element for coaction with the indicators of the indicator element at the front of the panel to visually indicate at the front of the panel movements thereof to shift the concealed movable switch contact to its selective working positions.

FRITZ KOCH. 

